In one type of electric motor such as shown, for example, in U.S. Pat. No. 3,567,973, the motor has a motor frame comprising a generally cylindrical shell and a pair of end members. The shell encircles the stator of the motor and the end members are fastened to the shell to rotatably support the shaft of a rotor in order to maintain a proper air gap between the motor and the stator as described in U.S. Pat. No. 3,567,973. The end members are held in position by tabs on the end members which engage notches and by portions of the shell being deformed over the outer surface of the end members.
Other methods of fastening the end members comprise the use of case bolts extending through the end members and spring clips which hook on the outer portion of the shell and over the end members. It is also been suggested that devices be provided that extend through the end shell and thereafter radially outwardly through openings in the shell. Welding and adhesive have also been used to hold the end head.
In such motors, provision is often made for mounting them by the use of studs that are staked and welded to the end members and extend generally perpendicular. The motors are subjected to shocks and vibration in use of the motor and the mounting of such studs is frequently weak and unable to support the motor during shipping and use. Another problem is the deflection of the end members where the end members are made of sheet metal.
Accordingly, among the objectives of the present invention are to provide a novel structure for mounting studs wherein the end member and stud are held securely to the shell, wherein the strength of the motor is increased, and wherein the stud is accurately held with its axis parallel to the axis of the motor.
In accordance with the invention, the shell has at least one circumferentially extending slot spaced from the edge of the shell and has a notch in the edge aligned with the slot. A spring nut has one end thereof hooked into the slot and extending along the outer surface of the shell. The nut extends inwardly through said notch in underlying relationship to the end member associated with the end of the shell. The end member has an opening therethrough and the spring nut has a threaded opening aligned with the opening in the end member. A stud has a threaded end and an enlarged shoulder portion, the threaded end extends through the opening in the end member and is threaded into the opening of the spring nut.